58e97e521c
Add the `LIBC_PREVENT_STRING_KERNEL` and `LIBC_PREVENT_STRING_USER` that are meant to be selected by the chip if no libc implementation is going to be built. If selected, neither NuttX's software version of the libc nor any architecture-specific implementation will be built in the kernel or in the userspace, respectively. In this case, the linker may provide a ROM-defined version of the libc functions instead.
113 lines
2.0 KiB
ArmAsm
113 lines
2.0 KiB
ArmAsm
/****************************************************************************
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* libs/libc/machine/risc-v/gnu/arch_memset.S
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*
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* Copyright (c) 2017 SiFive Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the FreeBSD License. This program is distributed in the hope that
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* it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
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* including the implied warranties of MERCHANTABILITY or FITNESS FOR
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* A PARTICULAR PURPOSE. A copy of this license is available at
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* http://www.opensource.org/licenses.
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*
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****************************************************************************/
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#include "libc.h"
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#ifdef LIBC_BUILD_STRING
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.text
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.global memset
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.type memset, @function
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memset:
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li t1, 15
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move a4, a0
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bleu a2, t1, .Ltiny
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and a5, a4, 15
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bnez a5, .Lmisaligned
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.Laligned:
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bnez a1, .Lwordify
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.Lwordified:
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and a3, a2, ~15
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and a2, a2, 15
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add a3, a3, a4
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#if __riscv_xlen == 64
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1:
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sd a1, 0(a4)
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sd a1, 8(a4)
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#else
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1:
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sw a1, 0(a4)
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sw a1, 4(a4)
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sw a1, 8(a4)
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sw a1, 12(a4)
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#endif
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add a4, a4, 16
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bltu a4, a3, 1b
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bnez a2, .Ltiny
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ret
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.Ltiny:
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sub a3, t1, a2
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sll a3, a3, 2
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1:
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auipc t0, %pcrel_hi(.Ltable)
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add a3, a3, t0
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.option push
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.option norvc
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.Ltable_misaligned:
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jr a3, %pcrel_lo(1b)
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.Ltable:
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sb a1,14(a4)
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sb a1,13(a4)
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sb a1,12(a4)
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sb a1,11(a4)
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sb a1,10(a4)
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sb a1, 9(a4)
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sb a1, 8(a4)
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sb a1, 7(a4)
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sb a1, 6(a4)
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sb a1, 5(a4)
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sb a1, 4(a4)
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sb a1, 3(a4)
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sb a1, 2(a4)
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sb a1, 1(a4)
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sb a1, 0(a4)
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.option pop
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ret
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.Lwordify:
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and a1, a1, 0xFF
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sll a3, a1, 8
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or a1, a1, a3
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sll a3, a1, 16
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or a1, a1, a3
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#if __riscv_xlen == 64
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sll a3, a1, 32
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or a1, a1, a3
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#endif
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j .Lwordified
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.Lmisaligned:
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sll a3, a5, 2
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1:
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auipc t0, %pcrel_hi(.Ltable_misaligned)
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add a3, a3, t0
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mv t0, ra
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jalr a3, %pcrel_lo(1b)
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mv ra, t0
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add a5, a5, -16
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sub a4, a4, a5
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add a2, a2, a5
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bleu a2, t1, .Ltiny
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j .Laligned
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.size memset, .-memset
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#endif
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